Easy Digital Downloads Duplicate Downloads Addon GPL Overview:

This plugin allows users to easily duplicate a download. When the “Duplicate” button is clicked, the details of a product are carried to a new draft. This is extremely useful for variation products because the variations do not need to be re-created for every single product.

Sale counts and earnings stats are not copied over.

After activated, this extension will add a “Duplicate” link to the Downloads list for each product: